Problem: $\begin{aligned}&\phantom{{\times}}{10}\\ \\ &\underline{\times5}\\ \\ \end{aligned}$ $~~$
We can think of ${10} \times {5}$ as ${10}$ rows of $5$ circles. How many circles are there? ${1}$ ${2}$ ${3}$ ${4}$ ${5}$ ${10}$ ${\color{#AA87FF}{1}}$ ${\color{#AA87FF}{2}}$ ${\color{#AA87FF}{3}}$ ${\color{#AA87FF}{4}}$ ${\color{#AA87FF}{5}}$ ${9}$ ${\color{#AA87FF}{6}}$ ${\color{#AA87FF}{7}}$ ${\color{#AA87FF}{8}}$ ${\color{#AA87FF}{9}}$ ${\color{#AA87FF}{10}}$ ${8}$ ${\color{#AA87FF}{11}}$ ${\color{#AA87FF}{12}}$ ${\color{#AA87FF}{13}}$ ${\color{#AA87FF}{14}}$ ${\color{#AA87FF}{15}}$ ${7}$ ${\color{#AA87FF}{16}}$ ${\color{#AA87FF}{17}}$ ${\color{#AA87FF}{18}}$ ${\color{#AA87FF}{19}}$ ${\color{#AA87FF}{20}}$ ${6}$ ${\color{#AA87FF}{21}}$ ${\color{#AA87FF}{22}}$ ${\color{#AA87FF}{23}}$ ${\color{#AA87FF}{24}}$ ${\color{#AA87FF}{25}}$ ${5}$ ${\color{#AA87FF}{26}}$ ${\color{#AA87FF}{27}}$ ${\color{#AA87FF}{28}}$ ${\color{#AA87FF}{29}}$ ${\color{#AA87FF}{30}}$ ${4}$ ${\color{#AA87FF}{31}}$ ${\color{#AA87FF}{32}}$ ${\color{#AA87FF}{33}}$ ${\color{#AA87FF}{34}}$ ${\color{#AA87FF}{35}}$ ${3}$ ${\color{#AA87FF}{36}}$ ${\color{#AA87FF}{37}}$ ${\color{#AA87FF}{38}}$ ${\color{#AA87FF}{39}}$ ${\color{#AA87FF}{40}}$ ${2}$ ${\color{#AA87FF}{41}}$ ${\color{#AA87FF}{42}}$ ${\color{#AA87FF}{43}}$ ${\color{#AA87FF}{44}}$ ${\color{#AA87FF}{45}}$ ${1}$ ${\color{#AA87FF}{46}}$ ${\color{#AA87FF}{47}}$ ${\color{#AA87FF}{48}}$ ${\color{#AA87FF}{49}}$ ${\color{#AA87FF}{50}}$ $\begin{aligned}&\phantom{{\times}}{10}\\ \\ &\underline{\times5}\\ \\ &~~C{50} \end{aligned}$